In 1879 both battalions took part in the Anglo-Zulu War, begun after a British invasion of Zululand, ruled by Cetshwayo. The 24th Regiment of Foot took part in the crossing of the Buffalo River on 11 January, entering Zululand. The first engagement (and the most disastrous for the British) came at Isandlwana. The British had pitched camp at Isandlwana and not established any fortifications due to the sheer size of the force, the hard ground and a shortage of entrenching tools. The 24th Foot provided most of the British force and when the overall commander, Lord Chelmsford, split his forces on 22 January to search for the Zulus, the 1st Battalion (5 companies) and a company of the 2nd Battalion were left behind to guard the camp, under the command of Lieutenant-Colonel Henry Pulleine (CO of the 1/24th Foot).[2]

A Zulu force of some 20,000 warriors attacked a portion of the British main column consisting of about 1,800 British, colonial and native troops and perhaps 400 civilians.[9] During the battle Lieutenant-Colonel Pulleine ordered Lieutenants Coghill and Melvill to save the Queen's Colour—the Regimental Colour was located at Helpmekaar with G Company. The two Lieutenants attempted to escape by crossing the Buffalo River where the Colour fell and was lost downstream, later being recovered. Both officers were killed. At this time the Victoria Cross (VC) was not awarded posthumously. This changed in the early 1900s when both Lieutenants were awarded posthumous Victoria Crosses for their bravery.[10] The Battle of Isandlwana was dramatized in the 1979 movie Zulu Dawn.[11]

A depiction of soldiers of the 24th Regiment repelling the Zulu attack on Rorke's Drift in January 1879

After the battle, some 4,000 to 5,000 Zulus headed for Rorke's Drift, a small missionary post garrisoned by a company of the 2/24th Foot, native levies and others under the command of Lieutenant Chard, Royal Engineers, the most senior officer of the 24th present being Lieutenant Gonville Bromhead. Two Boer cavalry officers, Lieutenants Adendorff and Vane, arrived to inform the garrison of the defeat at Isandlwana. The Acting Assistant Commissary James Dalton persuaded Bromhead and Chard to stay and the small garrison frantically prepared rudimentary fortifications.[12]

The Zulus first attacked at 4:30 pm. Throughout the day the garrison was attacked from all sides, including rifle fire from the heights above the garrison, and bitter hand-to-hand fighting often ensued. At one point the Zulus entered the hospital, which was stoutly defended by the wounded inside until it was set alight and eventually burnt down. The battle raged on into the early hours of 23 January but by dawn the Zulu Army had withdrawn. Lord Chelmsford and a column of British troops arrived soon afterwards. The garrison had suffered 15 killed during the battle (two died later) and 11 defenders were awarded the Victoria Cross for their distinguished defence of the post, 7 going to soldiers of the 24th Foot.[13] The stand at Rorke's Drift was immortalised in the 1964 movie Zulu.[14]

The regiment was not fundamentally affected by the Cardwell Reforms of the 1870s, which gave it a depot at The Barracks, Brecon from 1873, or by the Childers reforms of 1881 – as it already possessed two battalions, there was no need for it to amalgamate with another regiment.[15] Under the reforms the regiment became The South Wales Borderers on 1 July 1881.[16] This, understandably, led to the regiment having close links with South Wales.[17]

The 1st battalion was stationed in Egypt from 1892, then moved to British India.[18] The battalion had various postings, including at Peshawar until late 1902 when it was posted to Mean Meer outside Lahore.[19]

A 3rd (Militia) Battalion formed of the former Royal South Wales Borderers Militia, was embodied in January 1900, and the following month embarked for service in South Africa, arriving in Cape Town on the SS Cheshire in early March 1900.[23] A 4th (Militia) Battalion formed of the former Royal Montgomery Rifles was embodied in May 1900 and disembodied in December the same year.[24]

In 1908, the Volunteers and Militia were reorganised nationally, with the former becoming the Territorial Force and the latter the Special Reserve;[25] the regiment now had one Reserve battalion and one Territorial battalion.[26][1]

The 1st Battalion embarked for Ireland in June 1920 to maintain order during the Irish War of Independence and to Waziristan in February 1937 in connection with disturbances on the frontier.[4] Meanwhile, the 2nd Battalion was deployed to Palestine in 1936, returning home at the end of the year.[4]

Plaque commemorating the liberation of a bridge in Normandy by the 2nd Battalion, South Wales Borderers on D-Day in June 1944.

The 1st Battalion, as part of the 10th Indian Infantry Division, was sent to Iraq to quell a German-inspired uprising in Iraq in November 1941.[29] The battalion saw subsequent service in Iran. The battalion sustained enormous casualties in Libya near Tobruk when they lost around 500 officers and men captured or killed during a general retreat.[29] The battalion found itself cut off when the German forces outflanked them, the Commanding Officer, Lt. Col. F.R.G. Matthews, decided to attempt to escape around the enemy and break through to British lines. It turned into a disaster with only four officers and around one hundred men reaching Sollum.[29] To the surprise of the survivors the battalion was ordered to disband in Cyprus and the remnants of the battalion were transferred, with the exception of a small cadre that returned to the United Kingdom, to the 1st Battalion of the King's Own Royal Regiment (Lancaster). A few months later the battalion was re-formed from the cadre and the 4th Battalion, Monmouthshire Regiment.[29]

Upon the outbreak of the Second World War in September 1939, the 2nd Battalion was serving in Derry, Northern Ireland, under command of Northern Ireland District, having been there since December 1936.[30] In December 1939 the battalion left Northern Ireland and was sent to join the 148th Infantry Brigade of the 49th (West Riding) Infantry Division, a Territorial formation.[31] In April 1940 the battalion was again transferred to the newly created 24th Guards Brigade (Rupertforce), and took part in the Norwegian Campaign, and were among the first British troops to see action against the German Army in the Second World War.[32] The campaign failed and the brigade had to be evacuated. Casualties in the battalion, however, had been remarkably light, with only 13 wounded and 6 killed and two DCMs had been awarded.[33]

Infantrymen of the 2nd Battalion, South Wales Borderers hide themselves in a laurel bush during a brigade exercise near Ballymena in Northern Ireland, 19 September 1941.

The 1st Battalion was deployed to Palestine to deal with the volatile uprising in Palestine there in October 1945 and then moved to Cyprus in April 1946.[36] The 2nd Battalion was disbanded in May 1948 as a consequence of defence cuts implemented shortly after the Second World War.[36]

The regiment deployed to the Sudan in March 1949 and became part of the occupation force in Eritrea, a former Italian colony that was ruled by a British military administration, in January 1950.[36] The regiment arrived in Brunswick, West Germany as part of the British Army of the Rhine in January 1953 and was then deployed to Malaya in December 1955, as part of the response to the Malayan Emergency.[36] The regiment's conduct during the war compelled Field Marshal Sir Gerald Templer, a distinguished British officer and a man instrumental in the defeat of the communist terrorists during the Emergency, to state that, "there has been no better regiment in Malaya during the ten years of the emergency and very few as good".[37]

^An Authentic Account of our last attempt on the Coast of France by an Officer who miraculously escaped being cut to pieces, by Swimming to a Boat at a considerable distance from the shore., London, 1758.

^"Training Depots 1873–1881". Regiments.org. Archived from the original on 10 February 2006. Retrieved 16 October 2016.CS1 maint: BOT: original-url status unknown (link) The depot was the 25th Brigade Depot from 1873 to 1881, and the 24th Regimental District depot thereafter